Lehväslaiho's Medal

Awarded to players in medium tanks who destroy two enemy tanks or tank destroyers in one battle. The enemy vehicles must be at least one tier higher than the player's medium tank. Can be obtained in Random Battles only.

Spoiler

Question:

Assuming a rate of 1 kill of a random tier per game, how many straight bottom tier battles are required for this to occur?

I'm a simple person - If you don't dare to upload your replays, I assume you downloaded your skill